How is Industrial Silicon Powder Produced into High-Purity Silicon? Application of Raymond Mill in Manufacturing Process

Introduction

The production of high-purity silicon from industrial silicon powder is a critical process in the semiconductor and solar energy industries. Industrial silicon, typically with a purity of 98-99%, undergoes several purification steps to achieve the ultra-high purity required for electronic applications (99.9999% or higher). One of the key steps in this process is the grinding and milling of silicon materials to achieve the desired particle size distribution, which facilitates subsequent chemical purification processes. This article explores the transformation of industrial silicon powder into high-purity silicon and highlights the role of advanced grinding equipment, such as Raymond Mills, in optimizing this process.

From Industrial Silicon to High-Purity Silicon

Industrial silicon is produced by reducing silica (SiO₂) with carbon in an electric arc furnace. The resulting silicon has a purity of about 98-99%, with impurities such as iron, aluminum, calcium, and other metals. To achieve the high purity required for semiconductors and solar cells, industrial silicon must undergo further purification. The most common method is the Siemens process, which involves converting silicon into trichlorosilane (SiHCl₃), purifying it through distillation, and then depositing high-purity silicon via chemical vapor deposition (CVD).

However, before these chemical processes, the physical preparation of silicon powder is crucial. The silicon must be ground to a specific fineness to increase its surface area, which enhances the efficiency of subsequent reactions. The grinding process must be precise to avoid contamination and ensure uniform particle size.

The Role of Grinding in Silicon Purification

Grinding industrial silicon into fine powder is a critical step that directly impacts the efficiency of the purification process. The powder must have a consistent particle size to ensure uniform reaction rates during chemical processing. Traditional grinding methods, such as ball milling, can introduce contaminants and are often inefficient. Advanced grinding technologies, like Raymond Mills, offer a more efficient and contamination-free solution.

Raymond Mills, particularly the modern variants like the SCM Ultrafine Mill and MTW Series Trapezium Mill, are designed to handle hard and abrasive materials like silicon. These mills provide precise control over particle size distribution, which is essential for optimizing the subsequent chemical purification steps.

Application of Raymond Mill in Silicon Powder Production

Raymond Mills are widely used in the processing of industrial silicon due to their ability to produce fine and uniform powders with minimal contamination. The mills work by grinding materials between rollers and a rotating ring. The ground material is then classified to ensure only particles of the desired size are collected.

For silicon powder production, the key requirements are:

• High grinding efficiency to handle the hard and abrasive nature of silicon.
• Precise classification to achieve the target particle size distribution (typically between 325 to 2500 mesh).
• Low contamination to avoid introducing impurities that could affect the purity of the final product.
• Energy efficiency to reduce operational costs.

Our company’s SCM Ultrafine Mill is particularly well-suited for this application. With an output fineness of 325-2500 mesh (D97 ≤5μm) and a capacity of 0.5-25 tons per hour, it meets the rigorous demands of silicon powder production. The mill’s high-precision grading system ensures uniform particle size, while its durable design minimizes wear and contamination.

Another excellent option is the MTW Series Trapezium Mill, which offers a output fineness of 30-325 mesh and a capacity of 3-45 tons per hour. Its advanced design, including anti-wear shovel blades and optimized air channel, ensures efficient and contamination-free grinding. The mill’s锥齿轮整体传动 system provides high transmission efficiency, reducing energy consumption.

Technical Advantages of Our Grinding Equipment

Our grinding mills are designed with several key features that make them ideal for silicon powder production:

• High Efficiency and Energy Savings: The SCM Ultrafine Mill, for example, offers twice the capacity of jet mills while reducing energy consumption by 30%. This is achieved through intelligent control systems that automatically adjust to maintain consistent product fineness.
• Precise Classification: The vertical turbine classifier in the SCM Ultrafine Mill ensures accurate particle size切割, with no coarse powder mixing into the final product.
• Durability and Stability：Special materials for rollers and grinding rings extend their service life, and the bearing-free screw grinding cavity ensures stable operation.
• Environmental Protection: Pulse dust collectors exceed international standards, and soundproofing designs keep noise levels below 75dB.

Case Study: Silicon Powder Production Line

In a typical silicon powder production line, industrial silicon chunks are first crushed to a smaller size using a jaw crusher or hammer mill. The crushed material is then fed into a Raymond Mill for fine grinding. The ground powder is collected by a cyclone separator and pulse dust collector, ensuring high recovery rates and minimal dust emission.

For high-purity silicon production, the ground powder is further processed through chemical methods. The uniformity of the powder obtained from our mills enhances the efficiency of these chemical processes, leading to higher yields and purer final products.

Conclusion

The production of high-purity silicon from industrial silicon powder requires precise and efficient grinding equipment. Raymond Mills, such as our SCM Ultrafine Mill and MTW Series Trapezium Mill, play a crucial role in this process by providing fine, uniform, and contamination-free silicon powder. Their advanced features, including high efficiency, precise classification, and environmental friendliness, make them the ideal choice for modern silicon processing plants. By investing in our grinding technology, companies can optimize their silicon purification processes and achieve higher quality products with lower operational costs.